Superplastic metallic alloys, such as certain fine grain alloys of, for example, aluminum, magnesium, stainless steel and titanium, are relatively ductile and can undergo substantial tensile deformation in the presence of low shaping forces. Such materials are capable of being stretched and formed at suitable forming temperatures over a forming tool or into a die cavity to make complex shaped automotive body parts, or the like. This process is often referred to as superplastic forming.
Durable tools are available for the superplastic forming of aluminum alloy automotive body panels at temperatures of about 500° C. Such tools can often be used to make thousands of parts over the vehicle model period. Having developed the ability to make long production runs of a particular body panel design, designers now are interested in personalized, or individual decorative features, on only a part of the total number of panels produced on the durable, but expensive tool. It is now desirable to have the ability to make specially embossed panels during a production run.
Thus, it is an object of the present invention to provide a method of producing individualized patterns embossed on the surface of sheet metal panels or parts while using a forming tool. It is a more specific object of this invention to produce such personalized patterns on superplastic formable aluminum sheet metal alloys by interposing a suitable template between the sheet blank and the corresponding forming tool surface.